Objective  To review the efficacy and safety of high-dose, intermittent IV methylprednisolone (IVMP) as initial and long-term maintenance therapy for patients with CIDP.

Design  A retrospective medical record review between 1992 and 2003 of outcomes in CIDP, comparing patients in 3 cohorts depending on whether their primary treatment was IVMP, IVIg, or oral immunosuppression with prednisone or cyclosporine.

Setting  Washington University Neuromuscular Disease Center (St Louis, Mo), outpatient and inpatient records.

Patients  Patients with clinical and electrophysiologic evidence of CIDP were identified. Of 57 patients, 39 had sufficient data for full analysis.

Main Outcome Measures  Quantitative muscle testing with a handheld dynamometer. Medication profiles and adverse effects were also recorded.

Results  There was no significant difference in the mean improvement in quantitative muscle testing at 6 months or at the last clinic visit (an average of 4.5 years later) among the 3 groups. Fewer patients treated with oral immunosuppression improved at 6 months, but at the last visit, 81% to 88% improved in all 3 groups. Less weight gain and fewer cushingoid features affected patients treated with IVMP (19%) compared with patients treated with oral prednisone (58%).

Conclusions  Treatment of patients with CIDP using high-dose intermittent IVMP results in improved strength equal to that with IVIg and oral prednisone. The frequency of occurrences of weight gain and cushingoid features with IVMP is less than that with oral prednisone. Intravenous methylprednisolone should be considered for initial and long-term therapy in CIDP when patients have disability due to weakness.

Corticosteroids have been used to treat CIDP for almost 50 years. Controlled trials have supported the initial impression of efficacy,^2-3 and treatment with prednisone is now accepted as a first- or second-line therapy in CIDP. Although there is no standard regimen, corticosteroid treatment of CIDP often begins with daily oral prednisone, at high doses of up to 1 mg/kg.⁴ When improved strength is noted, usually after 1 to 3 months, a slow taper in total dose is begun and an effort is made to administer the drug on alternate days. Recurrence of symptoms during the taper necessitates reinstitution of higher doses of prednisone or the introduction of an alternative agent. A major drawback to long-term oral corticosteroid use is the common occurrence of adverse effects, including weight gain, cushingoid appearance, hyperglycemia, peptic ulcer disease, insomnia, infection, cataracts, and osteoporosis.^{1, 5} Alternate-day corticosteroid treatment probably has fewer adverse effects than daily dosing.

The mechanism of action of steroids is complex and likely involves multiple effects brought about by the activation of the glucocorticoid receptor.⁶ The glucocorticoid receptor binds to glucocorticoid-responsive elements located in the promoter regions of specific genes or to other nuclear transcription factors and can activate or inhibit gene transcription. Although prednisone has an elimination half-life of 1.5 to 4 hours, some of its effects might last for days because of changes in gene expression and protein synthesis.^5-6

We began using high-dose intermittent IV methylprednisolone (IVMP) as initial and long-term maintenance therapy for many patients with CIDP in 1992 in an attempt to find an alternative treatment regimen without the problems associated with long-term daily steroids. We now report a retrospective review of all CIDP patients treated in the Washington University Neuromuscular Disease Center (St Louis, Mo) between 1992 and 2003. We compared patients treated with IVMP, IVIg, and long-term oral immunosuppression. We evaluated the efficacy of each treatment by examining changes in quantitative strength measures, medication history, and adverse effects or complications with each type of treatment.